Objective      To identify genes involved in transforming growth factor beta-1 (TGF-β1)-induced smooth muscle differentiation of murine embryonic mesenchymal stem cell line C3H/10T1/2 (10T1/2 cells) by gene trap screening.       Methods      10T1/2 cells were induced by 5 ng/mL TGF-β1 to differentiate into smooth muscle cells (SMCs)

which were identified by cell morphology

RT-PCR identification of smooth muscle-related genes including alpha smooth muscle actin (αSMA)

smooth muscle 22 alpha (SM22α)

smooth muscle myosin heavy chain (SM-MHC)

serum response factor (SRF)

and immunocytochemical detection of αSMA. LacZ staining was used before and after TGF-β1 induced phenotypic modulation of gene trapped 10T1/2 clones to SMCs. Differentially expressed gene sequences were obtained by rapid amplification of cDNA ends (RACE) and in silico cloning. Then the sequences were searched in GenBank using BLAST algorithm for bioinformatics analysis and submitted to GenBank by its online software BankIt. The molecular weight and isoelectric point of differentially expressed genes were calculated by pI/Mw software. The mRNA expression of a novel gene (

mgt-16

) in the intestine

skeletal muscle and heart in BALB/c mice were detected by real-time PCR.       Results      The model of SMCs differentiation was successfully established based on cell morphology

RT-PCR and immunocytochemical staining. Two gene trapped clones with differential expression patterns of trapped genes were obtained by LacZ staining before and after TGF-β1 treatment. It was found that the trapped genes were mitochondrial ribosomal protein S6(Mrps6) and a novel gene (

mgt-16

) when the RACE-obtained sequences were searched in GenBank using BLAST algorithm. 

mgt-16

(GenBank accession No. GU266552) was mapped to mouse chromosome 19

encoded a protein whose length was 93 amino acids

molecular weight was 9 772.02 and isoelectric point was 6.04. Real-time PCR results showed that 

mgt-16

was highly expressed in the intestine

while lowl

y expressed in the skeletal muscle and heart.       Conclusion      Two differentially expressed genes

Mrps6 and novel gene

mgt-16

which may be involved in smooth muscle differentiation induced by TGF-β1

are obtained by gene trap screening. These findings may expand our understanding of TGF-β1 signaling pathway and the underlying molecular mechanisms involved in the differentiation of mesenchymal stem cells into SMCs.